Unfortunately in many industrialized countries, the incidence of human obesity is dramatically increasing. Moreover, human obesity is a common and costly nutritional problem in the United States in addition to being a devastating health problem. Obesity is characterized clinically by the accumulation of fat tissue (at times this is referred to as body fat content).
In humans, obesity is usually defined as a body fat content greater than about 25% of the total weight for males, or greater than about 30% of the total weight for females. However obesity exists outside those numbers too. Regardless of the cause of or extent of obesity, obesity is an ever present problem for Americans. But a fat content greater than about 18% for males and greater than about 22% for females can have untold consequences secondary to several mechanisms and disorders of metabolic function. For example, obesity can have a significant adverse impact on health care costs and provoke a higher risk of numerous illnesses, including heart attacks, strokes and diabetes.
In the case of diabetes, patients can lose limbs, eyesight and kidneys and hearts can fail so the potential results can be catastrophic and deadly.
Without being bound by theory, it is believed that obesity in humans results from an abnormal increase in white adipose tissue mass that occurs due to an increased number of adipocytes (hyperplasia) or from increased lipid mass accumulating in existing adipocytes. Obesity and the associated type two metabolic syndrome along with its clinical sequelae are among the major and the most rapidly increasing (epidemic) medical problems in America. However, to date, a lack of suitable adipocyte specific protein targets has unfortunately hampered progress in the development of effective therapeutic agents to combat the clinical sequelae of obesity.
Despite existing knowledge of the critical role of phospholipases in adipocyte signaling, enhanced clinical methodology and research tool and methods are highly needed for new obesity drugs and new methods for identifying useful drugs to treat obesity and over-weightness. It is highly desired to have knowledge and technology based on the specific types of phospholipases and lipases present in the adipocyte, or their mechanisms of regulation, and determine their natural substrates and roles in anabolic lipid metabolism, catabolic lipid metabolism or both (e.g. triglyceride cycling).